Midposition stop fixture for work transfer device

ABSTRACT

This midposition stop fixture consists of a base carrying an abutment block containing a clearance bore through which a reciprocable control rod connected to the work transfer device can move freely, except when it is intercepted by a stop block moved to intercepting position by the piston rod of a reversible fluid pressure cylinder mounted on the base. Reversal of the cylinder retracts the stop block from its forward position covering the clearance bore in the abutment block so that the reciprocable control rod connected to the work transfer device can pass freely through the clearance bore thereof, It then permits the work-carrying arm of the work transfer device to perform a full stroke and move beneath the forming element of the served machine, such as the punch of a forming press, rather than being intercepted in midstroke by the engagement of the control rod with the stop block while the two served machines are performing operation on their respective workpieces.

United States Patent Potter 1 1 Mar. 14, 1972 [72] Inventor: Ronald D. Potter, Waterford, Mich.

[73] Assignee: Erie Engineering Company, Troy, Mich.

[221 Filed: Apr. 6, 1970 [21] Appl. No.: 25,876

[52] US. CL... ....2l4/1B,192/116.5,214/l BB [51] Int. Cl ..F64d 71/00 [58] Field ofSearch ..l92/1l6.5;214/1 B, 1 BB, 1 BT, 214/1 R, 1 CM [56] References Cited UNITED STATES PATENTS 1,993,588 3/1935 Blanchard ..192/116.5

3,123,230 3/1964 Oppenheimer. ...2l4/l CM 2,637,789 5/1953 Critchfield ..70/ 181 Primary Examiner-Gerald M. Forlenza Assistant Examiner-George F. Abraham Att0rney-Barthel & Bugbee [5 7] ABSTRACT This midposition stop fixture consists of a base carrying an abutment block containing a clearance bore through which a reciprocable control rod connected to the work transfer device can move freely, except when it is intercepted by a stop block moved to intercepting position by the piston rod of a reversible fluid pressure cylinder mounted on the base. Reversal of the cylinder retracts the stop block from its forward position covering the clearance bore in the abutment block so that the reciprocable control rod connected to the work transfer device can pass freely through the clearance bore thereof, It then permits the work-carrying arm of the work transfer device to perform a full stroke and move beneath the forming element of the served machine, such as the punch of a forming press, rather than being intercepted in midstroke by the engagement of the control rod with the stop block while the two served machines are performing operation on their respective workpieces.

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INVENTOR RONALD D. POTTER BY Emmi,

ATTORNEYS MIDPOSITION STOP FIXTURE FOR WORK TRANSFER DEVICE This midposition stop fixture is provided for the Lifting and Swinging Work Transfer Device of Kirsch et al., US Pat. No. 3,406,837 of Oct. 22, 1968. Such a work transfer device, for example, removes a workpiece from one machine, transports it to another machine, and deposits it in that machine. The present midposition stop fixture is mounted between the two machines to move into and out of engagement with a moving control rod connected to the work transfer device so as to halt the latter midway between the two machines which it serves, so that these machines may operate freely without colliding with the work transfer device and thereby damaging it or either machine.

In the drawing,

FIG. 1 is a top plan view of the midposition stop fixture with its stop block in its retracted or rearward position, permitting a full stroke of the work transfer device;

FIG. 2 is a view similar to FIG. 1, but with the stop block in its advanced or forward position intercepting and halting the work transfer device in midstroke; and

FIG. 3 is a front elevation of the midposition stop fixture shown in FIG. 2 in its advanced or forward position.

Referring to the drawing in detail, FIGS. 1 to 3 inclusive show a midposition stop fixture, generally designated 10, employed in cooperation with the end 11 of a reciprocable rod 12 connected to a work transfer device (not shown) for either permitting the rod 12 to perform a full stroke of the work transfer device or alternatively halting the latter in midstroke while the machines served by the work transfer device perform their working strokes. The work transfer device includes a base plate 14 which is bolted as at 16 to a stationary member or structure 18 preferably disposed intermediate the two machines. Welded or otherwise fixedly secured to the base plate 14 is an upstanding abutment block 20 which has a clearance bore or aperture 22 therethrough aligned with the reciprocable control rod 12 so as to permit passage of the latter therethrough to perform a full stroke unless intercepted. Such interception is selectively performed by a stop block 24 having a bottom surface 26 slidably mounted along the top surface 28 of the base plate 14.

Extending rearwardly from the stop block 24 is a tongue 30 bored to receive a shouldered pivot screw 32 which likewise this stage in the operation of the served machines, it is necestransfer device or to either of the served machines might be caused by a collision between the moving parts thereof. Accordingly, in the stroke-intercepting position of the midposition stop fixture 10 shown in FIGS. 2 and 3, the stop block 54 has been moved into its stop position adjacent the abutment block 20 by the forward motion of the piston rod 44 brought about by admitting pressure fluid to the rearward fluid service port 56 and discharging fluid from the forward service port 54. This action causes the piston head (not shown) attached to the piston rod 44 to move forward to the right into the stroke-intercepting position shown in FIGS. 2 and 3. In the latter position, the stop block 24 is positioned directly in front of the clearance bore 22 in the abutment block 20 so that it is engaged by the end 11 of the reciprocable control rod 12 connected to the work transfer device. In this manner, the latter is halted in a position intermediate the two machines being passes through the alignedly-bored spaced parallel arms 34 of a clevis 36 and is retained in position by a nut 38 thereon. The clevis 36 at its rearward end is bored and threaded at 40 to receive the correspondingly-threaded forward end 42 of a piston rod 44. The latter passes through the reduced-diameter externally threaded forward portion 46 of the forward cylinder head 48 of a fluid pressure cylinder, generally designated 50, containing a reciprocable piston head (not shown) connected to the piston rod 44 and having a rearward cylinder head 52. The cylinder heads 48 and 52 are provided with threaded fluid service ports 54 and 56 respectively which are connected by suitable flexible hoses or other conduits to a source of pressure fluid, such as a compressed air line, by way of a suitable reversing valve (not shown).

The fluid pressure cylinder is held in its position by an angle bracket 58 which is drilled for the passage of bolts 60 threaded into the correspondingly-threaded base plate 14. A nut 62 threaded onto the reduced diameter forward portion 46 of the cylinder head 48 against the angle bracket 58 secures the cylinder 50 firmly to the angle bracket 58 and thence to the base plate 14. The angle bracket 62 is provided with a bore 64 for the passage of the reduced diameter forward portion 46 of the forward cylinder head 48.

In the operation of the midposition stop fixture 10, let it be assumed that the stop block 24 is in its advanced or intercepting position shown in FIGS. 2 and 3 and that either or both of the machines being served by the work transfer device connected to the reciprocable control rod 12 are in operation, carrying out operations upontheir respective workpieces. At

served, as it is prevented from moving through a complete work transfer stroke by the obstacle presented temporarily by the stop block 24 against the abutment block 20 and covering the clearance bore 22.

When, however, either or both of the served machines have completed their working strokes and have retracted their work-forming members, such as punches, pressure fluid is admitted to the forward service port 54 and discharge through the rearaard service port 56, causing the piston within the cylinder 50 to move rearwardly to the left, carrying with it the piston rod 44 and the stop block 24 through the intermediate action of the clevis 36. Thereupon, the stop block 24 is retracted from its forward position adjacent the abutment block 20 by moving rearwardly to the left into the retracted position shown in FIG. 1. The clearance bore 22 in the abutment block 20 is then uncovered and no obstacle is then presented for the reciprocable control rod 12 to move into it. As a result, the work transfer device connected thereto is permitted to perform a complete working stroke, either depositing a workpiece in one machine or removing it from the other machine, as the case may be.

I claim:

1. A midposition stop fixture for a work transfer device having movable work transfer mechanism therein, said stop fixture comprising a base structure having a stationary upstanding abutment element with a clearance bore therein,

a reciprocable control member of smaller diameter than said bore adapted to be operatively connected to the work transfer mechanism in stroke-controlling relationship therewith, said control member being movably mounted adjacent said base structure in alignment with said clearance bore for reciprocation relatively thereto,

a stop member mounted on said base structure for motion toward and away from said abutment member between bore-covering and bore-uncovering positions relatively thereto,

and a fluid pressure cylinder having a reciprocable piston operatively connected to said stop member for selectively moving said stop member into and out of covering relationship with said clearance bore, said fluid pressure cylinder being a double-acting cylinder having fluid-pressure actuation of said piston in opposite directions of motion thereof.

2. A midposition stop fixture, according to claim 1, wherein said stop member comprises a block resting upon said base structure and slidably engageable therewith.

3. A midposition stop fixture, according to claim 1, wherein said stop member is pivotally connected to' said piston.

4. A midposition fixture, according to claim 3, wherein a clevis comprises the pivotal connection said piston and said stop member. 

1. A midposition stop fixture for a wOrk transfer device having movable work transfer mechanism therein, said stop fixture comprising a base structure having a stationary upstanding abutment element with a clearance bore therein, a reciprocable control member of smaller diameter than said bore adapted to be operatively connected to the work transfer mechanism in stroke-controlling relationship therewith, said control member being movably mounted adjacent said base structure in alignment with said clearance bore for reciprocation relatively thereto, a stop member mounted on said base structure for motion toward and away from said abutment member between bore-covering and bore-uncovering positions relatively thereto, and a fluid pressure cylinder having a reciprocable piston operatively connected to said stop member for selectively moving said stop member into and out of covering relationship with said clearance bore, said fluid pressure cylinder being a double-acting cylinder having fluid-pressure actuation of said piston in opposite directions of motion thereof.
 2. A midposition stop fixture, according to claim 1, wherein said stop member comprises a block resting upon said base structure and slidably engageable therewith.
 3. A midposition stop fixture, according to claim 1, wherein said stop member is pivotally connected to said piston.
 4. A midposition fixture, according to claim 3, wherein a clevis comprises the pivotal connection said piston and said stop member. 